Encased refractory brick



Nov. 29, 1960 w. H. MYERS ET AL 0 ENCASED REFRACTORY BRICK Filed Jan.28, 1957 INVENTORS -10 /v. Myses m 2: f fimeese w M,Mwfi% 779'6/3flmeugy;

United Sttes Patent F ENCASED REFRACTORY BRICK William H. Myers, GlenBuruie, and John A. Garber,

Severna, Md., assignors to Harbison-Walker Refractories Company,Pittsburgh, Pa., a corporation of Pennsylvania Filed Jan. 28, 1957, Ser.No. 636,557

1 Claim. (Cl. 50416) This invention, relates to blocks for forming thewalls and roofs of industrial furnaces, and more particularly to thosein which refractory bricks are enclosed in metal cases.

It is common practice to surround the sides of basic refractory brickswith thin sheet metal cases which oxidize when the furnace is put inoperation and thereby bond the bricks together. Such cases generallyhave open ends, but sometimes they have end flanges bent across the endsof the brick. Such flanges at the bottom of suspended bricks are likelyto become so hot as to swing down and form no support for the brick. Insuch instances or when a case has no ends, a broken section of a brickcan slide out of the case and thereby leave a thin spot in the furnaceroof at that point. Also, in spite of efforts to firmly fasten the casesto the bricks, it has been found that broken pieces of bricks or anentire brick may slide out of a case during handling and drop on thefoot of a workman.

The push for production from industrial furnaces requires that thebricks be heated up and in production as soon as possible. Frequently,the bricks are unable to tolerate this treatment, with the result thatthe ends are spalled off by the thermal shock. This is not much of aproblem after the refractory becomes matured or burned in, because thewall or roof then acts very much like a single unit. However, on theinitial heat-up, the bricks behave as small units.

It is among the objects of this invention to provide a furnace brickthat is surrounded by a metal case, from which the encased brick cannotescape, and which includes a protective sheet of metal to cushion thebrick against the most severe temperature variations.

According to this invention the sides of a refractory brick are engagedby a metal case. Extending across an end of the brick is a metalstirrup, the ends of which extend a short distance along the sides ofthe case and are secured to it. Preferably, there is such a stirrup ateach end of the brick. They prevent the brick from sliding out eitherend of the case. In some cases, the stirrups are provided with a coatingthat will retard their oxidation.

The preferred embodiment of the invention is illustrated in theaccompanying drawings, in which Fig. 1 is a perspective view of ourblock; and

Figs. 2 and 3 are reduced vertical sections taken on the lines II-II andIIIIII, respectively, of Fig. 1.

Referring to the drawings, a basic refractory brick 1, which is uprightwhen designed for suspension as part of a furnace roof, is provided nearits upper end with a lateral recess 2 for receiving the stem and foot ofa hanger (not shown). The brick can be made in one piece as shown, or intwo or more pieces separated along vertical planes. In the latter event,the brick units generally are separated by a metal plate as shown inRochow Patent 2,465,170. Whether the brick is made in one or more parts,at least three sides of it are engaged by a sheet metal case.Preferably, the case extends all the way around the brick and is formedin two parts from metal channels 3 and 4, the side flanges of whichoverlap Patented Nov. 29, 1960 ICC each other at opposite sides of thebrick. Such channels can readily be applied to a preformed brick, or abrick can be molded into one of the channels and then the other channelapplied.

It is a feature of this invention that means are provided for preventingthe brick or a fractured section of it from sliding endwise out of thecase accidentally. Accordingly, a metal stirrup 6 is secured to each endof the case after the case and brick have been assembled. Each stirrupis formed from a U-shaped strip of metal that extends across an end ofthe brick and then vertically for a short distance along the oppositesides of the block. The vertical end portions of the stirrup aresecurely attached to the sides of the case whether the case consists ofone channel or two of them. When the brick is provided with hangerrecess 2 that cuts into its upper surface, the upper stirrup is madenarrow enough to fit between the recess and the opposite edge of thebrick. To avoid having to use stirrups of two different sizes, the lowerstirrup may be made the same width as the upper one. A very convenientway of fastening the stirrups is to insert their ends between theoverlapping side flanges of the case and then spot weld the flanges tothe stirrups, as at 7 in Fig. 1. Such welding secures the stirrups andsimultaneously fastens the two halves of the case together. The stirrupsthen form end walls for the case to prevent the brick from coming out.If desired, however, the stirrups can be fastened to the case in someother way, such as by an adhesive or by interlocking members. In somecases it may be felt that the upper stirrup is not necessary and can beomitted. When the brick is formed in two units separated by a verticalmetal plate, the stirrups make it unnecessary to provide any other meansfor holding the plate between the two units.

The case is supposed to oxidize when it is heated in the furnace and tothereby bond the bricks together. However, there is no necessity for thestirrups to oxidize, and their oxidation may even be undesirable in somecases by making them too weak to support the bricks. In such cases, itis desirable to first coat the stirrups with a suitable oxidationpreventing material so that they will not burn away so rapidly. Theutility of the stirrups depends on their metallic properties, ratherthan upon their conversion to oxides. Protective coatings suitable forthis purpose are known. They may be formed from refractory oxides suchas magnesia, beryllia, alumina, zirconia and silica.

According to the provisions of the patent statutes, we have explainedthe principle of our invention and have illustrated and described whatwe now consider to represent its best embodiment. However, we desire tohave it understood that, within the scope of the appended claim, theinvention may be practiced otherwise than as specifically illustratedand described.

We claim:

A furnace block comprising a refractory brick having opposite endsconnected by two sides, a two-part metal case engaging the sides of thebrick and formed from sheet metal channels having overlapping sideflanges, a metal stirrup extending across each end of the brick and partway along its sides between said overlapping flanges, and spot weldsjoining the end portions of the stirrups to the side flanges of bothchannels.

References Cited in the file of this patent UNITED STATES PATENTS1,949,079 Loeffier Feb. 17, 1934 2,187,669 Stewart Jan. 16, 19402,216,813 Goldschmidt Oct. 8, 1940 2,247,376 Heuer July 1, 19412,736,187 Coffman et al. Feb. 28, 1956

